You would need to amend your return to apply for it, if you qualify. First, check to see if it's already on your return. Then, see if you qualify (below).
How do I check in TurboTax to see if I claimed the EIC and/or ACTC?
https://ttlc.intuit.com/replies/5591940
What are the qualifications for the Earned Income Credit
(EIC or EITC)?
https://ttlc.intuit.com/replies/3299933
AMEND
Once
your return has been submitted for e-file, you cannot make any
changes until it is either Accepted or Rejected. The IRS will not receive
the change. Then, when/if the
Return is accepted, you will file a new amended return. If
your return is Rejected, you can go ahead and make the change and then
resubmit the e-file.
Amending is done on Form 1040X. Also, if your
return is accepted, you should not try to amend your return until it has been
fully processed and you have received your refund or your payment has cleared.
Amended returns have
to be printed and filed by mail. It can take the IRS up to 12 weeks or
longer to process them. If you are due a larger refund than on your
original return, your amended return should only show the difference and you
will receive a separate check for it. If you owe money on your amended
return, it will show only the new amount owed, you will have to mail a check
with the return.
How to Amend?
https://ttlc.intuit.com/replies/3288565
